It is an unprecedented bit of time travel for a sport that was born on frozen ponds, nurtured in unheated rinks, and conjures up images of woolen hats and knotted scarves.

At South Boston Waterfront bars this week, as the Bruins wrested Game 3 from the Chicago Blackhawks, the pumped-up crowds could easily have been cast for a tiki party. No one asked for hot chocolate on a day when the temperature hit 87 degrees in Boston.

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“When you’re playing hockey in the summertime, it means the team is awesome,” said Adam Rousseau, 29, a former college hockey player from Tewksbury. In other words, the late date means a championship is possible.

But the summerlike heat and humidity are taking a toll on the TD Garden ice, which has become rougher and riddled with ruts as the games progress.

“I feel terrible for the poor guys in the ice crew who were working so hard to get a decent surface,” said Jack Edwards, the Bruins play-by-play announcer for NESN. “There was nothing they could do about it. There were puddles on the ice at the beginning of the second and third periods.”

For the players, Edwards said, the game becomes simpler, if not visibly slower, as they are forced to adapt to a climate that makes pinpoint passing more difficult.

Game 4 of the best-of-seven series — which the Bruins lead, 2 games to 1 — is Wednesday night in Boston. Game 5, which will officially be played in summer, is set for Saturday in Chicago.

Although climate control is much more advanced than in the old Boston Garden, where the Bruins were asked to skate in circles to disperse fog during timeouts in the 1988 playoffs, the combination of high temperatures, humidity, and body heat from 17,000 fans can gain an edge over the ice.

Still, for fans and many businesses, these warm-weather Bruins are a reason to feel good about the late, late show that has become the Stanley Cup Final. The series has become appointment television for Boston sports fans, and bars with open decks are crowded with patrons watching hockey under the stars.

“The roof deck’s open, and we turn up the sound,” said Roger Berkowitz, president of Legal Sea Foods, whose Harborside restaurant in South Boston is drawing Bruins fans for an al fresco experience. “It does seem a little odd, though. It almost seems too warm to be watching hockey.”

Edwards described the sensation as “bizarre,” particularly when he leaves an arena after calling a late-season game.

“It’s when I go outside, and I’m motioning to draw my scarf tight, and I don’t even have a topcoat,” Edwards said. “That’s when the shock sets in: It’s a pleasant evening, and it’s summer.”

‘It does seem a little odd. . . . It almost seems too warm to be watching hockey.’

The march into summer — the latest season in National Hockey League history — is the result of a players’ lockout that cut 34 games from the season, which did not begin until January. As a result, the playoffs were extended deeper into June. If the Bruins and Blackhawks play a full series, Game 7 will be next Wednesday, less than a week before July.

During Game 3 on Monday, patrons at the Atlantic Beer Garden on the South Boston Waterfront said the victory was just as enjoyable on a sultry evening as it would have been in a February blizzard.

“It doesn’t really matter that it’s warm out; it’s professional sports,” said Cabell Wallace, 45, a flip-flop-wearing visitor from Williamsburg, Va. “They work their whole life to get on this ice. They don’t care.”

Rousseau, a Maine native who played hockey for St. Michael’s College in Colchester, Vt.,
said, the tropical conditions outside TD Garden made the inside performance more impressive. “These guys have to be that much better conditioned to play in the summer. They have to focus so much more.”

That focus, ratcheted up during the playoffs, will be followed by weeks of deep decompression. But for these players, their offseason will be the shortest in NHL history.

Edwards predicted that regular-season games next season will begin earlier than normal, probably in the first week of October, because of the need to break in early 2014 for the Winter Olympics.

Berkowitz, the Legal Sea Foods president, thinks this “winter sport” will end quickly, with a Bruins trophy.

“I think they have momentum, and I think they can do it in five,” Berkowitz said. “I’m not sure if that’s better for business or not.”

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